Effect of short-term rainfall change on plant community characteristics in desert steppe

In order to study the effects of long-term grazing and short-term rainfall variations on vegetation characteristics of a grassland ecosystem, an experiment using different rainfall gradients (50% reduction, ambient, 50% increase, and 100% increase in environmental rainfall) was conducted on the site of a long-term manipulative stocking rate experiment (no grazing, light grazing, moderate grazing, and heavy grazing), and the response (in terms of individual quantities, species diversity and aboveground biomass of the plant community) to rainfall changes was analyzed. The results showed that: 1) variations in long-term grazing and short-term rainfall had significant effects on community coverage (P<0.05) (community coverage decreased with increasing grazing intensities but increased with increasing rainfall); 2) the rainfall variations had significant effects on species diversity (P<0.05) (there was an increase of 22 species with 100% increase in environmental rainfall under moderate grazing conditions); 3) the long-term grazing and short-term rainfall variations had significant effects on aboveground biomass (P<0.05) (The highest aboveground biomass was 408.3 g·m-2 under ambient rainfall under no-grazing conditions, and the lowest aboveground biomass was 118.2 g·m-2 with 50% reduction in environmental rainfall in heavy grazing conditions).